﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

class N_K_PartII
{
    static void Main()
    {
        int n;
        int k;
        do
        {
            Console.Write("Enter k > 1: ");
            k = Convert.ToInt32(Console.ReadLine());
            Console.Write("Enter n > {0}: ", k);
            n = Convert.ToInt32(Console.ReadLine());
            if ((k < 1) || (n < k)) 
            {
                Console.WriteLine("!!BEEP");
            }
        } while ((k < 1) || (n < k));
        decimal facrotial = 1;
        for (int i = (k + 1); i <= n; i++) 
        {
            facrotial *= i;
        }
        Console.WriteLine(facrotial);
    }
}

